The Strain Index is very helpful in measuring ergonomic risk of the distal upper extremity. A good website to check out is the following:

http://personal.health.usf.edu/tbernard/HollowHills/StrainIndexM12.pdf

for the pdf or the following for the excel file

http://personal.health.usf.edu/tbernard/HollowHills/StrainIndex22.xls